PROBLEM
Eysenck has stated that there are two independent factors in the psychiatric field that are associated with psychotic and neurotic disorders. He has labeled these factors psychoticism and neuroticism, respectively. A third dimension, extraversion, also has been described and is considered to be orthogonal to the previously mentioned factors. With respect to the interaction between the neuroticism and extraversion dimensions, he considered hysterics and psychopaths to be extraverted. Dysthymics (a term used synonymously with neurotics by the current authors) were considered to be introverted. If Eysenck's premise could be demonstrated, then these diagnostic categories could be used as criterion groups for the validation of tests for extraversion. The presence of extraversion or introversion also should prove valuable in the diagnosis of neurosis or psychopathy.
Sigal, Star and Franks(5) found that hysterics couldn't be used as criterion groups because they tended to score along with normals near the center of the introversion-extraversion continuum. They also stated that psychopaths scored significantly higher than dysthymics on the extraversion scale, but their number was small and Sigal, et al. (5) considered their conclusions tentative. I n a later study Eysenck ( l ) concurred that hysterics scored close to normals on extraversion scales and indicated that psychopaths are significantly more extraverted than dysthgmics.
Foulds 0 ) took issue with the above-mentioned studies on three main points. He proposed that Sigal, et aE. and Eysenck may have found more dysthymic introverts than psychopathic introverts simply because inore dysthymic patients, both introverted and extraverted, seek psychiatric help.
Foulds also indicated that the above authors shifted their argument from frequency of occurrence t o degree of extraversion. This implies that while most extraverts in a psychiatric population might be psychopaths, the few extraverts who are dysthymic might be even more extraverted than any of the psychopaths. The use of mean extraversion scores thus is open to question and may be misleading when two groups are compared for incidence of extraversion.
Fould's third point of disagreement with the two studies concerned Eysenck's conclusion that more psychopaths are extraverts and that most dysthymics are introverts. This was considered an empirical question by the current authors and provided the hypothesis for this study.
I n his description of the abnormal personality Research has been equivocal, however", 5).